[tcbmhell]

Originally Posted by SmartSaves

Thanks ChiefOne. Are these your sequence/steps?

1. Unlock the vehicle
2. Open the hood
3. Connect the output cables to (+) and (-)
4. Plug the charger to wall outlet
5. Leave the hood open
6. Lock the vehicle

I am also interested to know if you plugged the charger to wall outlet before or after the vehicle instrument cluster turns off...or like the vehicle went to sleep mode. What I did was plug the charger to outlet until it went to sleep mode（all lights in the car were off).

[ChiefOne]

SmartSaves and tcbmhell
The last time when I was able to successfully charge the battery, I followed the following steps -
1. Unlock the vehicle
2. Open the hood
3. Connect the output cables to (+) and (-)
4. Plug the charger into the wall outlet
- Make sure that the BMW Charger (CAR Normal) light OR
CTEK charger (CAR + AGM) light is on
5. Gently lower the hood (do not close all the way)
- Leave the vehicle unlocked
- After every few hours, keep checking the temp of the charger by touching it.
- Did not attempt to wake the vehicle by opening the door, or going near it with the key in the pocket. Once or twice I did open the door to see the central display, but in general, left it as is.


This time around, I am following all the same steps except I have locked the vehicle and I am not unlocking and checking the central console. I am using the BMW charger. So far, close to six hours and still counting on stage 3.

[ChiefOne]

Originally Posted by tcbmhell

I am also interested to know if you plugged the charger to wall outlet before or after the vehicle instrument cluster turns off...or like the vehicle went to sleep mode. What I did was plug the charger to outlet until it went to sleep mode（all lights in the car were off).

I did not wait for the instrument cluster to turn off. I just connected the terminals under the hood and moved on to connecting the charger to the wall outlet.

[ChiefOne]

Originally Posted by SmartSaves

Thanks ChiefOne. Are these your sequence/steps?

1. Unlock the vehicle
2. Open the hood
3. Connect the output cables to (+) and (-)
4. Plug the charger to wall outlet
5. Leave the hood open
6. Lock the vehicle

Another observation: the 18 AWG wire on the CTEK charger is pretty thin IMO, it is enough to carry 4.3 Ampere current, but not heavy-duty built. During bulk charge stage (first 80%) the CTEK connectors could become very hot due to having thin cables, this will result charging voltage being lower than needed, for example the charging voltage for AGM battery could be just 14.1 Volts instead of 14.7 Volts as described. If you have access to charging voltage graph you'll see this. One remedy is to replace the connectors with thicker cables.

I tried the following charging calculator and it shows an estimate on how many hours it takes to charge. Temperature is a factor and it takes longer to charge the last 20% of the battery - known as absorption. First 80% bulk charging should happen quickly.

https://www.meracalculator.com/physi...harge-time.php

This is a good find SmartSaves and totally makes sense.

[tcbmhell]

18AWG is ok.

[tcbmhell]

Update--


I noticed after I connected the charger, all the lights in the car went off shortly, a few mins later I heard sounds from engine compartment like the car was trying to reboot something. At the same time, hazard switch red triangle, crystal knob light, parking light, these lights came back on. The lights were on and off, accompanied by some sounds from engine compartment. This kind of process kept looping in the charging process. Both locked and unlocked and the result was the same.

I have to unplug the Noco, it stayed at 50% stage for more than 40 hours.

[ChiefOne]

Originally Posted by tcbmhell

Update--


I noticed after I connected the charger, all the lights in the car went off shortly, a few mins later I heard sounds from engine compartment like the car was trying to reboot something. At the same time, hazard switch red triangle, crystal knob light, parking light, these lights came back on. The lights were on and off, accompanied by some sounds from engine compartment. This kind of process kept looping in the charging process. Both locked and unlocked and the result was the same.

I have to unplug the Noco, it stayed at 50% stage for more than 40 hours.

That is absolutely bizarre. In my various charging attempts, I never observed such behavior. But then I have never used NOCO, I always used CTEK or BMW charger. I am not sure if such an issue warrants a visit to the service center, I think it would but I will let others chime as well.

[tcbmhell]

Originally Posted by ChiefOne

That is absolutely bizarre. In my various charging attempts, I never observed such behavior. But then I have never used NOCO, I always used CTEK or BMW charger. I am not sure if such an issue warrants a visit to the service center, I think it would but I will let others chime as well.

It wouldn’t happen if I removed the charger.

I thinks it's not the issue of Noco. I tried CTEK, NOCO, and Deltran, the same situation. I don’t know if I triggered something, because I’ve been standing by the car observing. I read this thread，https://g05.bimmerpost.com/forums/sh...0&postcount=37
May it's the reason.

BTW，does your BMW charger work if you lock the door?

[ChiefOne]

Originally Posted by tcbmhell

It wouldn’t happen if I removed the charger.

I thinks it's not the issue of Noco. I tried CTEK, NOCO, and Deltran, the same situation. I don’t know if I triggered something, because I’ve been standing by the car observing. I read this thread，https://g05.bimmerpost.com/forums/sh...0&postcount=37
May it's the reason.

BTW，does your BMW charger work if you lock the door?

Possibly, however, I never enabled the feature to automatic lock when leaving. If you think it's worth it, please disable that feature and see if it acts differently.

My last attempt to charge using the BMW charger with vehicle locked did not work. I left it for about 10 hours and the status stayed stuck at stage 3.

I then unlocked the vehicle, and reconnected the charger, left it for about 12 hours, the same situation. It was still stuck at stage 3 after 12 hours. I don't believe that the battery that was fully charged a few days back, not even a week, and is driven on and off since then, will lose that much charge that it will take 12 + hours to charge.

I just now disconnected the BMW charger and plugged-in the CTEK charger, doors unlocked, it switched to stage 3 almost instantly. It's fricking confusing. Will keep updating the status.

[tcbmhell]

Originally Posted by ChiefOne

Possibly, however, I never enabled the feature to automatic lock when leaving. If you think it's worth it, please disable that feature and see if it acts differently.

My last attempt to charge using the BMW charger with vehicle locked did not work. I left it for about 10 hours and the status stayed stuck at stage 3.

I then unlocked the vehicle, and reconnected the charger, left it for about 12 hours, the same situation. It was still stuck at stage 3 after 12 hours. I don't believe that the battery that was fully charged a few days back, not even a week, and is driven on and off since then, will lose that much charge that it will take 12 + hours to charge.

I just now disconnected the BMW charger and plugged-in the CTEK charger, doors unlocked, it switched to stage 3 almost instantly. It's fricking confusing. Will keep updating the status.

Very confusing

[SmartSaves]

May be just use the digital key card to unlock the vehicle? It has very short range and it won't trigger automatic lock and unlock process. I have both turned off.

Another distinction we should keep in mind that battery tender and chargers are bit different. At 4 amp I would call these tender or maintainer. Modern charger could automatically push more current and slow itself down (variable rate).

I am hearing charging amp rate should be set at approximately 10% of the battery capacity. In our case that would be around 10 amp. Ideally the charger should slowdown the charging amp automatically when the battery is 80% charged.

[tcbmhell]

Originally Posted by SmartSaves

May be just use the digital key card to unlock the vehicle? It has very short range and it won't trigger automatic lock and unlock process. I have both turned off.

Another distinction we should keep in mind that battery tender and chargers are bit different. At 4 amp I would call these tender or maintainer. Modern charger could automatically push more current and slow itself down (variable rate).

I am hearing charging amp rate should be set at approximately 10% of the battery capacity. In our case that would be around 10 amp. Ideally the charger should slowdown the charging amp automatically when the battery is 80% charged.

No matter what it calls, the tender output 14~15v and 4.3A, the voltage is enough to be able to fully charge a battery. The current only determines the charging time.

[biterror]

Originally Posted by SmartSaves

I am hearing charging amp rate should be set at approximately 10% of the battery capacity. In our case that would be around 10 amp. Ideally the charger should slowdown the charging amp automatically when the battery is 80% charged.

The chargers are basically current limited constant voltage sources (with some added intelligence). First they charge at a constant current until the battery voltage reaches a certain value. After this, they charge at a constant voltage (and current "automatically" drops as the battery charges up) until current drops under a certain value and the charger switches to float/maintain mode.

So, what you're wishing for is actually happening. :-)

[SmartSaves]

I did two experiments. Car is locked and parked inside the garage, no key fobs with me:

1. Tried opening the driver and rear passenger doors by pulling the door handle. Pretty obvious, nothing happened, X5 remained in sleep, no lights lit inside.

2. Tried opening the rear hatch by hand. Sounded like an electric motor woke up with grinding noise, but did nothing, and stopped after few seconds. Hazard light, gear shifter light, parking button light, switch panel between the door and steering wheel (fog light, automatic headlight etc.) lit on and stayed on. Went back to check about 15 minutes later, all the lights were turned off.

It is interesting that rear hatch door handle wakes up the X5 somewhat even if the vehicle is locked. I believe automatic door unlocking setup does something similar (I don't use this feature).

[tcbmhell]

Originally Posted by SmartSaves

I did two experiments. Car is locked and parked inside the garage, no key fobs with me:

1. Tried opening the driver and rear passenger doors by pulling the door handle. Pretty obvious, nothing happened, X5 remained in sleep, no lights lit inside.

2. Tried opening the rear hatch by hand. Sounded like an electric motor woke up with grinding noise, but did nothing, and stopped after few seconds. Hazard light, gear shifter light, parking button light, switch panel between the door and steering wheel (fog light, automatic headlight etc.) lit on and stayed on. Went back to check about 15 minutes later, all the lights were turned off.

It is interesting that rear hatch door handle wakes up the X5 somewhat even if the vehicle is locked. I believe automatic door unlocking setup does something similar (I don't use this feature).

Interesting. I just tested it and it's exactly the same as you described. I also noticed if I tried to kick to open the hatch, the hazard light would on. Contactless locking and unlocking features were off.

What happened was like that when my battery was charging, but I didn't tried to open the rear hatch.

[Renzm]

Safe to say this behaviour seems to be pretty much identical across all models with the 48v system. What many are describing with the X5 here is the same as with our G20 and likely G30 as well. Put my CTEK MXS 5.0 charger on with the bonnet/hood just resting and not closed, and after about 15 hours it's still on step 3 of its charging process. I have noticed the very same as what is being reported here on the G20 with things like the hazard indicator switch and auto light switch staying illuminated, seems as though it is definitely still in a "wakened" state somehow.

[SmartSaves]

We are inquiring why it is taking so long in stage 3. We know bulk charging happens in stage 3, but the question is for how long it should stay in that position before the charger automatically terminate charging.

Some basic definitions:

Voltage [V]: is like water flowing through pipes. How much water is flowing.

Current [A]: is the rate of flow, at what rate the current is flowing, proportional to the diameter of a pipe or the amount of water flowing at that pressure, measured in amps (A).

I wonder what is the maximum voltage the CTEK charger could provide considering the constraints below (I don't have a multi-meter):

1. Cold temperatures efficiency loss
2. Low AWG rating and thin plastic insulation
3. Length of the extension cable (if any)

If the voltage is limited by the constraints above then we need to try a better charger, AGM battery need higher voltage.

On a side note, I also think many chargers will have hard time stay in the maintenance mode because the modern vehicles draws more power even when it is turned off.

[jad03060]

Voltage is more like pressure and current is the volume. You can have pressure without volume, and a battery won't accept current unless first, there's a complete connection, and second, if the input voltage exceeds the current battery state of charge which is what pushes it into the battery...not enough pressure or no complete circuit, no current will flow.

If the charging device does not show current, and you have a meter that has sufficient range to test it, you could hook a multimeter in line and check what actual current is flowing into the battery.

Most battery tenders estimate the charge state by how much current is going into the battery and the voltage level.

[gianlucatest]

Hi, I'm from G20 forum, my car is 48v so I have your same problem.
I used a multimeter to monitor the voltage during trickle charge and discovered that, instead of having steady and stable voltage during phase 3, it periodically drops under 13 volts, and that happens just before/after I hear the noises of the various control units restarting.
In my opinion the problem is not the charger that doesn't deliver enough power but some kind of circuit protection :/

[tcbmhell]

Originally Posted by gianlucatest

Hi, I'm from G20 forum, my car is 48v so I have your same problem.
I used a multimeter to monitor the voltage during trickle charge and discovered that, instead of having steady and stable voltage during phase 3, it periodically drops under 13 volts, and that happens just before/after I hear the noises of the various control units restarting.
In my opinion the problem is not the charger that doesn't deliver enough power but some kind of circuit protection :/

I think this's why the charger stays at stage 3. The charger determines whether the battery is fully charged by measuring the voltage. Because some control units restart or wake up periodically, the battery will have load and drop under 13 volts, the charger will think the battery is not charged correctly, so stay at stage 3 keep charging. The strange thing is that if you don’t connect the charger, the control units won't restart. We don’t know what triggered the awakening of some units.

[biterror]

Originally Posted by gianlucatest

Hi, I'm from G20 forum, my car is 48v so I have your same problem.
I used a multimeter to monitor the voltage during trickle charge and discovered that, instead of having steady and stable voltage during phase 3, it periodically drops under 13 volts, and that happens just before/after I hear the noises of the various control units restarting.
In my opinion the problem is not the charger that doesn't deliver enough power but some kind of circuit protection :/

It sounds the car is waking up for some reason and consuming more power so the battery voltage drops (the current consumption is higher than what the charger can supply).

It would be nice to know the logic in these cars - what and why they are doing - or if this waking up is a bug.

[tcbmhell]

Originally Posted by biterror

It sounds the car is waking up for some reason and consuming more power so the battery voltage drops (the current consumption is higher than what the charger can supply).

It would be nice to know the logic in these cars - what and why they are doing - or if this waking up is a bug.

Actually the battery voltage will drop off if it has any load, even just seconds. If the load is disconnected after seconds, the voltage will rise back. But once the charger detects the voltage drop, it thinks the battery is not charged correctly and keep bulk charging.